Evidence for steroid "receptors" is being sought in cytosol and nuclear fractions prepared from human renal adenocarcinomas and from an estrogen-induced renal adenocarcinoma in male hamsters (Kirkman tumor). If "receptors" for estradiol, progesterone or testosterone are found, these steroids will be tested for effects on tumor growth. BIBLIOGRAPHIC REFERENCE: Anderson, N.S. III, Y. David and D.D. Fanestil. Estrogen Binding Proteins in the Kidneys of Hamsters with Estradiol Induced Renal Carcinoma. Fed. Proc., 1976, in press.